Alternative to Mouse?

Is there any relatively inexpensive alternative to having a mouse, preferably some kind of pen?

I have to do a heck of a lot of product shot cutouts in photoshop and I am beginning to get painful repetitive strain injury. I've tried different desk and seat positions, different mice etc but the injury has set in and there doesn't seem to be any stopping it. Taking time off work to rest in not an option for me.

I've been looking at pen mice but haven't come across any that appear to be good for photoshop cutouts etc, and many tablets seem to be for illustration work.

I have had a look at these on the Apple site and they appear to be the kind of thing that I'm after. However, some of the reviews weren't so go with regards to mouse control and i only need the mouse functionality.

I don't have experience with using the Bamboos, but do with other tablets, and tbh, I can't really use them for doing 'mouse stuff'.

I did have one many years ago that had the option of using it like a mouse (in the sense that the cursor stayed where you left it, regardless of where you positioned the pen on the tablet) but I think that was because it was a cheap, crappy one.

I only have a mouse because I like to play online games which needs the 8 buttons on my gaming mouse ^^;

I love my wacom tablet (to the point I have 3) I have a small bamboo for use with my laptop its small and light perfect for on the move. My intuos which my sister is borrowing because I got a new Intuos 2 which has a slightly higher spec and pressure sensitivity which i need for my digital painting.

If you are getting RSI you need to move your arm/mouse position before it gets bad or invest in a more ergonomically shaped mouse (if you are using an apple one) that can help too. But you can get small cheap tablets that will do you just as well as any mouse for 'mouse stuff' as they generally force you to move your arm that little bit more preventing rsi